;; Copyright London Stock Exchange Group 2016 All Rights Reserved.
;;
;; Licensed under the Apache License, Version 2.0 (the "License");
;; you may not use this file except in compliance with the License.
;; You may obtain a copy of the License at
;;
;;                  http://www.apache.org/licenses/LICENSE-2.0
;;
;; Unless required by applicable law or agreed to in writing, software
;; distributed under the License is distributed on an "AS IS" BASIS,
;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
;; See the License for the specific language governing permissions and
;; limitations under the License.

(ns chaintool.ast
  (:require [clojure.zip :as zip])
  (:refer-clojure :exclude [find]))

;;-----------------------------------------------------------------
;; find a specific element in the AST
;;-----------------------------------------------------------------
(defn find [term ast]
  (loop [loc ast]
    (cond

      (or (nil? loc) (zip/end? loc))
      nil

      (= (zip/node loc) term)
      (zip/up loc)

      :else
      (recur (zip/next loc)))))
